Existing electrical wires and cable and their associated methods of installation require the use of tools, such as wire strippers and cutters, to expose the conductive elements of the wires in preparation for their connection to an electrical system. This process takes both time and skill and can be time consuming, even for experienced installers, especially when the time consumed is considered over the course of a project. Errors during this operation may also result in the insulation surrounding the conductor or the wire itself being compromised or severed, requiring additional time to be spent on repair, if noticed by the installer, before the work can proceed.
In addition to time and skill requirements, this seemingly simple task also occasionally results in workplace injuries. This is, in part, because the preferred industry tool for stripping such a cable is a utility knife. According to the Massachusetts governmental website, the second most likely reason for an 18-24 year old male to visit the emergency room with a work related injury is being cut or pierced. Notably, 15,154 or 28.1% of visits in Massachusetts emergency rooms result from such injuries annually in Massachusetts alone. Nationally, emergency rooms treat over 750,000 patients annually with work-related cut or pierce injuries. A wire that omitted the use of a utility knife from the stripping operation would inevitably lead to a reduction in such injuries and could help to save millions of dollars annually.
Cables, which contain a plurality of individually-sheathed wires, present an even larger challenge to installers and a significantly larger risk of costly and/or time consuming errors being made. With cables, the outer sheathing must be cut away to expose the jacketing of individual wires for stripping, further increasing the time an electrician, HVAC tech, professional installer, homeowner or other person installing the wiring must spend preparing the wires for installation and the risk of damage to the underlying conductor from accidental puncture of the protective jacket during sheathing removal.
A somewhat related problem involves ductless mini-split A/C systems. In recent years, mini-split ductless AC systems have become popular. These systems are similar to traditional central air conditioning systems in that they locate the noisiest part of the system, the compressor and associated hardware, outdoors. Such systems, however, do not require extensive ductwork to be installed within the home, thus making them a reasonable and cost-effective upgrade to an existing structure.
While the systems themselves are relatively easy to install, relative to traditional centralized air conditioning systems, the cabling for such systems is relatively complicated, requiring AC power wires, DC signal or communications conductors and non-current carrying ground wires to function, each of which must be separated by sheathing in addition to that of the individual wires. There is currently no cable that can provide ease of use, durability and the required connectors for installation of such a system, while meeting code requirements.
Another problem area for electricians is thermostat wiring. Thermostats typically require at least four wires to function and these wires are typically fed into a relatively small area, commonly referred to as a junction box, before having their conductive elements exposed. The restricted space available to the electrician in such an area increases the probability of a costly error, namely the unintentional severing of a wire or laceration injury.
Specialty thermostat cables, such as the “Honeywell Thermostat Cable”, are available that attempt to address these issues. These cables contain a string, which runs the length of the cable, parallel to the wires contained therein. This string is intended to be pulled substantially perpendicularly to the lengthwise direction of the cable, thereby focusing the force exerted on a narrow section of the outer cable jacket, initiating a tear that can then be used to expose the length of wire necessary to complete the installation. These specialty cables, however, have a number of problems and even create problems in addition to those encountered when using traditional cabling. One problem with such specialty cables is that the string is often not very effective at allowing the installer to strip the outer jacket, typically requiring significant force to be exerted by the electrician, which can result in damage to the fine wires commonly used for this application. Another issue is that these strings must be embedded in the cable, requiring additional space and materials while increasing complexity of the manufacture; this technique cannot be used for fine wires. Still another issue is that this string must be cut after it has served its purpose, resulting in an additional opportunity for installer error that could result in injury or accidental severing of a needed wire.
What is needed, therefore, are wires and cables that do not require the use of tools to expose the conductors within, enabling their tool-less installation, particularly wires and cables suitable for use in the installation of mini-split ductless AC systems and thermostats.